growfs, old disks, gvinum - filesystem expansion and corruption

[Lee Damon]

 > = Eric Anderson
>>  = me
...
>> My questions are:
>> 1. Is there any way to clean up the old file system cruft without 
>> crashing/trashing/deleting the system?
> 
> You could use dd to write zeros over the old areas to wipe out the old 
> filesystem data.  Careful!

Is there a way to find out which parts of the "disk" are currently not 
in use by an active gvinum area?

>> 2. What tool should I be using to calve off slices of a 'huge' drive 
>> and later expand it?
> 
> Why not use fdisk/bsdlabel?

I didn't think that could be done with a live/active/mounted drive or 
with more than a handful of slices.  [The system currently has 16 
mounted gvinum-based filesystems, some of which will end up being made 
of 3 (or more) individual slices based on growth].

nomad